European temperatures spike, causing heatwaves
A new study has revealed that climate change has significantly increased heatwave-related deaths in European cities, with the 2025 summer heatwave causing approximately 1,500 excess deaths across 12 major cities due to human-driven warming.
Key findings include:
- The heatwave during June 23 to July 2, 2025, was 2 to 4 degrees Celsius hotter because of climate change, making heatwaves more intense and deadly. - A total of 2,300 heat-related deaths were recorded in the 12 cities studied, of which approximately 65% (1,500 deaths) were attributable to climate change. - These cities span countries including Italy, Spain, Portugal, France, the UK, Greece, Croatia, and Hungary, indicating a broad geographic impact across Europe. - The research was conducted rapidly by a collaboration between Imperial College London, the London School of Hygiene & Tropical Medicine, and the Grantham Institute, using historical weather data to compare the observed heatwave to a scenario without climate change. - Vulnerable groups such as the elderly, women (especially pregnant), children, and those with pre-existing health conditions were disproportionately affected, highlighting the silent but deadly nature of heatwaves.
The European Centre for Medium-Range Weather Forecasts (ECMWF) operates the climate change service. Researchers emphasize that this rapid attribution study is among the first to quantify climate change’s direct role in heatwave mortality so quickly, demonstrating that climate change is an “absolute game changer” increasing both the intensity and fatality of extreme heat events.
The findings underline the urgent need for stronger climate mitigation to reduce greenhouse gas emissions, as further warming will likely increase the frequency and severity of deadly heatwaves, especially in urban areas.
June 2025 was globally the third warmest on record with an average surface temperature of 16.46°C, following June 2023 and 2024 as the warmest months on record. The previous June record in Europe was 20.43°C in 2003.
Heatwaves are expected to occur more frequently, become more intense, and affect more people across Europe. The study serves as a stark reminder of the growing public health crisis posed by extreme heat events, and the urgent need for action to combat climate change.
[1] Imperial College London. (2025). Rapid attribution study on the 2025 European heatwave. Retrieved from https://www.imperial.ac.uk/media/imperial-college/science-technology/grantham-institute/documents/2025-european-heatwave-rapid-attribution-study.pdf [2] London School of Hygiene & Tropical Medicine. (2025). Climate change and heatwave mortality in European cities. Retrieved from https://www.lshtm.ac.uk/newsevents/news/2025/climate-change-and-heatwave-mortality-european-cities [3] European Centre for Medium-Range Weather Forecasts. (2025). Climate change service. Retrieved from https://www.ecmwf.int/en/climate-research/climate-change-service [4] Copernicus Climate Change Service. (2025). Temperature records. Retrieved from https://climate.copernicus.eu/climate-reports/global-state-of-the-climate/2025/temperature-records
The Commission has also been consulted on the issues of science, health-and-wellness, climate-change, and environmental-science, given the urgent need for stronger mitigation against climate change following the revelation that human-driven warming significantly increased heatwave-related deaths in European cities. The swift collaboration between research institutions such as Imperial College London, the London School of Hygiene & Tropical Medicine, and the Grantham Institute, which conducted a study on the 2025 European heatwave, further underscores the critical role science plays in understanding and addressing climate change's impact on public health.
